Great, thanks for that Joey. I found another of your posts with details on yesterday, and I ended up doing the following last night (almost exactly the same as yours) ....
1 can Wilko Stout
227g (half a tin) black treacle
200g cocoa powder
500g (1 bag) medium DME
500g (half a bag) dextrose
I rehydrated the yeast at 23C with a little dextrose while I was mixing the above and pitched it into the wort also at 23C. It's been in the fermenting fridge at 19C overnight (approx 12 hours) and I dropped it down to 18C this morning.
OG was 1048 when mixed to 20L, and if it drops to 1008 as per the instructions then it should come out at about 5.2%.
I plan to leave it alone at 18C for two weeks, then rack off to another vessel and cold crash at 5C for a week or two before transferring to a Corny keg. I've already got some old Guinness taps ready so I'm hoping for a nice smooth pint some time next month :grin: